A liquid crystal panel used in a liquid crystal display device such as a liquid crystal television, for example, does not emit light, and thus, it is necessary to provide a separate backlight device as an illumination device. One known example of this type of liquid crystal display device is that disclosed in Patent Document 1 below.
The device disclosed in Patent Document 1 illuminates a liquid crystal panel with light from a light source, and projects an image generated by the transmitted light onto a screen using a projection lens. In this type of device, a metal-halide lamp is used as the light source, and thus, there was a problem that over an extended period of time, color unevenness developed in the emitted light. As a countermeasure, in Patent Document 1, deterioration of the displayed image is mitigated by modifying the image signal displayed in the liquid crystal panel based on the real usage amount of the light source.